Mononeuropathies

Question 1

General causes of mononeuropathies (2)

Answer 1

• Trauma

- Entrapment due to tumour

Question 2

Most common mononeuropathy

Answer 2

Carpal tunnel syndrome

Question 3

Proximal/anterior interosseus median nerve lesions presentation

Answer 3

• Precision grip loss
• Weakness of flexion of distal phalanx (fingertips) of thumb + index finger
• Can’t make a fist
• Can’t feel thumb index and middle finger

Question 4

Cause of proximal/anterior interosseus median nerve lesions (2)

Answer 4

• Dislocations at elbow level

- Blunt trauma at elbow level

Question 5

Two main types of median nerve lesions

Answer 5

• Distal medial nerve injuries i.e carpal tunnel syndrome

- Anterior interosseus/proximal median nerve lesions

Question 6

Radial nerve (C5-T1) lesion presentation (3)

Answer 6

• Wrist and finger drop
• Anatomical snuffbox sensory loss
• BEAST (posterior forearm) weakness
  Brachioradialis
  Extenstors
  Abductor pollicis longus
  Supinator
  Triceps

Question 7

Why do radial nerve lesions cause wrist drop? (2)

Answer 7

• All muscles in posterior compartment innervated by radial nerve
• Injury = unopposed wrist flexion

Question 8

Cause of radial nerve lesion and why? (2)

Answer 8

Humeral shaft fracture

- Due to compression against humerus

Question 9

Axillary nerve injury (C5-C6)

Answer 9

• Deltoid pain
• Loss of shoulder movement/senstation
• Weakness deltoid/teres minor (abduction + external rotation)

Question 10

Axillary nerve injury common cause

Answer 10

Humeral neck fracture

Question 11

Ulnar nerve C7-T1 injury common cause

Answer 11

Medial epicondylar fracture (elbow trauma)

Question 12

Ulnar nerve injury signs (7)

Answer 12

• Weakness/wasting of medial (ulnar side) wrist flexors
• Interossei wasting (can’t do “fingers crossed”)
• Medial 2 lumbricals wasting (claw hand)
• Hypothenar eminence wasting
• Weak 5th digit abduction
• 4th/5th DIP joint flexion
• Sensory loss over ulnar (medial) side of ring + little finger

Question 13

Phrenic nerve injury signs

Answer 13

• Orthopnoea

- Raised hemidiaphragm in Cxray

Question 14

Phrenic nerve injury causes (5)

Answer 14

• Lung cancer
• TB
• Myeloma
• Thoracic surgery
• Infections e.g HIV/HZV/Lyme

Question 15

Peroneal nerve injury presentation

Answer 15

• Foot drop

- Dorsiflexion and eversion of foot weakness

Question 16

Peroneal nerve injury cause

Answer 16

Trauma to head of fibula

Question 17

Lateral cutaneous nerve of thigh (L2-L3) injury presentation

Answer 17

Meralgia paraesthetica

Anterolateral burning thigh pain

Question 18

Lateral cutaneous nerve of thigh (L2-L3) cause

Answer 18

Entrapment under inguinal ligament

Question 19

Axillary nerve injury presentation (2)

Answer 19

• Inability to elbow flex

- Deltoid sensation loss

Question 20

Musculocutaenous nerve injury presentation (2)

Answer 20

• Elbow weakness (biceps)

- Lateral forearm sensation loss